JPS60151851A - Duplicating method of optical disk substrate - Google Patents

Abstract

PURPOSE:To reproduce easily numbers of optical disk substrates and eliminate problems of safety and sanitation by using no liquid lacquer which sets by ultraviolet-ray irradiation as a material for transfer, and using a substrate which has a soft photosensitive resin layer on the surface. CONSTITUTION:The flat substrate of plastic, glass, etc., has the soft ultraviolet- setting resin layer on the surface is used, and this substrate is pressed against a transfer pattern across the soft resin layer and irradiated with ultraviolet rays simultaneously to set the soft resin layer; and the resin layer which is set is peeled off the transfer pattern together with the substrate to duplicate an optical disk to which information pattern of ruggedness formed on the surface of the transfer pattern is transferred faithfully. An operator is allowed to duplicate numbers of disks easily with a compact making machine and there is no problem in terms of safety and sanitation.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides optical disk substrates such as playback-only video disks and audio disks, and disk memories that can be recorded, played back, and (erased) using photosensitive resin. Concerning the method of copying.

[Technical background of the invention and its problems]

Generally, information recording carriers for video discs and digital audio discs have a large number of signal pits formed on the surface, while information recording carriers for disc memories have guide grooves for tracking the optical head on a high-definition net. (pre-groove) is formed.

The pits and guide grooves are fine uneven patterns on the order of submicrons, and information recording carriers having these uneven patterns are generally copied in large quantities from a transfer mold called a stamper. As this duplication method, the injection method and the 2P method (a duplication method using an ultraviolet curable lacquer as a transfer material) are mainly known. The injection method has the drawbacks that the device becomes large and the transfer accuracy is not very good. On the other hand, compared to the injection method, the 2P method requires more compact manufacturing equipment and has superior transfer accuracy, but it is difficult to fill the information surface of the transfer mold with UV-curable lacquer without introducing air bubbles. In addition, the reactive monomers contained in the ultraviolet curable lacquers are generally highly toxic to the skin and to the oral cavity, posing health and safety problems for workers during duplication.

[Purpose of the invention]

An object of the present invention is to eliminate the drawbacks of the above-mentioned conventional methods and to provide a method for duplicating optical disk substrates that can be easily reproduced in large quantities without requiring special techniques.

That is, the aim is to provide a complete duplication method that allows an operator to easily make large quantities of duplication using a compact molding machine, and which poses no health and safety problems.

[Summary of the invention]

The present invention involves preparing a flat substrate made of plastic or glass on the surface of which a soft resin layer that can be cured by ultraviolet rays is prepared in advance, and sandwiching the soft resin layer between the substrate and a transfer mold. The soft resin layer is hardened by irradiating it with ultraviolet rays while being pressed, and then this hardened resin layer is peeled off from the transfer mold along with the substrate. Information on the irregularities formed on the surface of the transfer mold is then obtained. This is an optical disc reproduction method that faithfully transfers a pattern onto a substrate.

The components of the soft resin layer that cures with ultraviolet light include at least a photoinitiator that absorbs ultraviolet light and generates active species;
It contains reactive oligomers or reactive monomers that undergo chain polymerization due to the generated active species, and the resin layer as a whole does not appear to be liquid but is a soft solid. In addition, as a resin layer component, a binding polymer with excellent adhesion to the substrate, such as polymethyl methacrylate, is used.

Polyurethane, polyester, etc. can also be added. Furthermore, antistatic agents, curing accelerators, etc. can also be added.

As a method for providing such a soft ultraviolet ray-curable resin layer on the entire substrate, 1) a spinner coating method, 2) a roll coating method 9, etc. are suitable.

The spinner coating method involves dissolving the above-mentioned resin layer components in a solvent to form a low-viscosity solution, applying this to the desired thickness on the substrate using a spinner, and then drying the solvent without coating. . On the other hand, the roll coating method is a method in which the photosensitive resin is transferred from the roll side to the substrate side and applied when the substrate passes between two rolls.

In this method, it is still preferable to dissolve the photosensitive resin in a solvent to make it have a low viscosity, since this results in a smooth coated surface.

Rolls, presses, air pressure, etc. can be used as a means to press the soft photosensitive resin layer provided on such a flat substrate onto the transfer mold, but more specifically, It is preferable to press the photosensitive resin layer in a spherically symmetrically deformed state to prevent air bubbles from being trapped in the photosensitive resin layer.

Further, as the ultraviolet light for curing the photosensitive resin layer, a low pressure mercury lamp, a high pressure mercury lamp, a metal halide lamp, etc. are used.

Generally, a metal stamper, especially a nickel stamper made by electroforming, is used as a transfer mold. As the main component of the photosensitive resin, it is preferable to use polybutadiene or a copolymer of polybutadiene and epoxy resin which is completely acrylic-modified or methacrylic-modified. Furthermore, in order to improve the separation from the nickel stamper, it is sufficient to apply the release agent completely on the stamper.

Since dust adheres to the soft photosensitive resin layer provided on such a flat substrate during storage, it is preferable to cover it with a protective sheet (for example, a polyester film with good mold releasability).

[Embodiments of the invention]

Epoxybutadiene oligomer (EPB14 manufactured by Nippon Soda)
90 parts by weight of a reactive oligomer obtained by acrylic modification of epoxy equivalent (epoxy equivalent: 400-500), PMMA (Dupont
10 parts by weight of photoinitiator (2008)
4 parts by weight of 2-dimethoxy-2-phenylacetophenone) were dissolved in butyl acetate to prepare a photosensitive resin solution having a concentration of 300 parts by weight. An acrylic substrate (outer diameter 305+m, thickness 1.2
A soft photosensitive resin layer having a thickness of 1 μm was formed by coating and drying the photosensitive resin layer on top of the photosensitive resin (Fig. 1 (1)). In order to prevent dust from adhering during storage, a polyester film was pasted onto this photosensitive resin layer using a roll (Fig. 1 (2)). The transfer mold used was a nickel stamper f for a video disc, which was made by electroforming and transferred from a resist master disc on which image information was recorded on the entire surface with uneven signal focus. After pressing the acrylic substrate with the entire photosensitive resin layer on the nickel stump bar with a roll so as to completely sandwich the photosensitive resin layer (FIG. 1 (4)). The photosensitive resin layer was cured by irradiating ultraviolet light from the substrate side (FIG. 1 (5)). The ultraviolet lamp used was an 80 W/crn water-cooled straight tube high-pressure mercury lamp.

When the cured photosensitive resin layer is peeled off from the nickel stamper along with the acrylic substrate (FIG. 1 (6)).

A video disc substrate was obtained in which the signal was clearly focused.

〔Effect of the invention〕

This duplication method does not use a liquid lacquer that is cured by ultraviolet light as a transfer material, but uses a soft photosensitive resin).
Since a substrate provided on the entire surface is used, it is easy to make large quantities of copies, and there are no health and safety problems.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram illustrating the method of manufacturing an optical disk substrate according to the present invention step by step. 1... Soft photosensitive resin layer 2... Substrate 3... Laminate 4... Pressure roll 5... Transfer mold representative patent attorney Keisuke Norichika (1 person) % 1%, l η ゝ′ −1 ＼−

Claims (1)

[Claims] 1) A soft resin layer that cures with ultraviolet rays provided on a flat substrate is irradiated with ultraviolet rays while being pressed onto a transfer mold, and then the resin layer is peeled off from the transfer mold together with the substrate to perform the transfer. formed on the mold